Interesting question. I probably keep mine set in place longer than most during rests because I play with the "dry, grip" method vs. the wet slippery method. Like to know everything is in place before the passage starts. However, I was playing in front of a guy who played lead for both BB circus and the Ice Follies. The only comment about my playing he made is I need to immediately relax the embashure on rests. He seemed to think that relaxing helped endurance, even micro rests.